The present invention relates generally to the field of sensor systems. More particularly, the present invention relates to a system for synchronizing the outputs of multiple analog sensors.
In many fields, multiple sensor systems are used to obtain better data or to provide new types of measurements. For example, in the medical field, the quality of heart rate data from a heart rate monitor may be improved by using data from other sensors, such as accelerometers or gyroscopic sensors, to remove motion artifacts that may affect the heart rate data. Another example is sensing the amount of pressure applied to a foot when a knee is bent. The data from pressure sensors on the foot may be combined with data from accelerometers around the knee. One more situation may occur even when dealing with single-modality sensors as well. For example, pressure sensors placed on the foot may have different designs than pressure sensors placed on an arm or a head band due to the expected range of pressure values.
In order to be useful, the data from the multiple sensors must be synchronized for analysis. Data from current multi-sensor systems may not be synchronized on account of differing latencies in the electronics of the various sensors in the analog domain. Different types of sensors use different electronic circuits to produce their outputs depending on their modality (e.g., pressure, sound, image, olfactory, temperature, etc.) and other characteristics (e.g., data rates, range of values, resolution of measurements, etc.). Thus, events that are detected by the sensors at the same time may not be output by the electronics of the respective sensors at the same time.